I plan to go the The Kings Arms on Tooley St, east of Tower Bridge Road soon. I've now had two friends separately tell me how nice it was to be in there. I've been passed enough times and it does look nice with its over the top lampshade festival.
I second the recommendation of The Kings Arms, especially in the evening.
A while ago I had some Swedish visitors, who were keen on doing a pub crawl. Or a "pub round" as they called it. There'a a link to my custom made SE1 pub cral below. We did about two thirds of it, ending up at the Roebuck around 12:30am... could have done more if we started earlier!